The trypanosome causing disease in man in Nyasaland.—The naturally infected dog strain. Part IV.—Experiments on immunity

The following experiments were undertaken to find out whether the Naturally Infected Dog strain of the trypanosome causing disease in man in Nyasaland would protect against the other strains. These different strains have been described in previous papers as the “ Human,” the “ Wild Game,” the “WildGlossina morsitans ,” “Zululand, 1913,” etc., and here they will be known by the same names. “ Human ” will therefore mean a strain of this species of trypanosome coming from man, “ WildG. morsitans ” from a tsetse fly, and so on. These immunity experiments were necessarily one-sided, as it was, with three exceptions, only animals which had recovered from the weaker Naturally Infected Dog strain which were available.